php - Sending a function to library in Codeigniter -

this works in controller.

$this->load->driver('cache');  //working // $data['advisory']=$advisory = $this->cache->memcached->get('advisory'); // if(! $advisory) // { //     $data['advisory']=$advisory = $this->mhomework->getbyadvisory($this->teacherid); //     $this->cache->memcached->save('advisory' , $advisory); // } 

i made library make following can use others.

function cache($key, $data)  {     $this->ci->load->driver('cache');     $cache = $this->ci->cache->memcached->get($key);      if (!$cache) {         // there's been miss, run our data function , store         $cache = $data($ci);         //$cache = $data;         $this->ci->cache->memcached->save($key, $cache);     }      return $cache; } 

and in controller changed following gives error.

$data['advisory'] = $this->hwtracker->cache('advisory.'.$this->teacherid, function(&$ci){         return $ci->mhomework->getbyadvisory($this->teacherid);     });  // error  call member function getbyadvisory() on non-object in ... controller // message: trying property of non-object 

my question how can send function library in codeigniter? or can i?

update:　　　　

function getbyadvisory($id){         　　$q="select *, studentid, count(studentid),be_user_profiles.first_name, 　　 　　　　　　　be_user_profiles.last_name             be_user_profiles             left join hw_homework             on be_user_profiles.user_id= hw_homework.studentid             be_user_profiles.advisor = $id             group be_user_profiles.user_id             order count(studentid) desc";         $query = $this->db->query($q);          if ($query->num_rows() > 0)         {             foreach ($query->result_array() $row)             {                 $data[] = $row;             }          }         else         {             $data = false;         }         $query->free_result();         return $data;     } 

please change library this

function cache($key, $data)  {  $this->ci->load->driver('cache');   //bind key here  $key_details = $data.$key;   $cache = $this->ci->cache->memcached->get($key_details);   if (!$cache) {      // there's been miss, run our data function , store     $cache = $this->$data($key);      //$cache = $data;     $this->ci->cache->memcached->save($key, $cache);  }     return $cache; }  //new advisory function in library function advisory($teacherid){      return $this->ci->mhomework->getbyadvisory($teacherid); } 

and in controller call this

$data['advisory'] = $this->hwtracker->cache($this->teacherid,'advisory');